I think OP is wrong about Sony having to pay more to acquire games, infact Sony have got themselves into a good position.
Basically what is happening is developers are getting extra revenue a whole year after launch for a game they dont expect to gain much more money from.
Looking at this, the other developers missing out are going to sony and asking for their old games to be put on PS+ too, giving sony more and more bargaining power, assuming only 2 games per platform can go on PS+ at once.







